Speed control of engine pump via summing differential

ABSTRACT

A fluid pumping system for an engine includes a pump; a summing differential connected to the pump; a gearbox connected to the summing differential, wherein the gearbox causes the pump to rotate to provide a fluid flow in the engine via the summing differential; and a motor connected to the summing differential, wherein the motor adjusts a rotational speed of the pump via the summing differential

FIELD OF INVENTION

The subject matter disclosed herein generally pertains to the field of a control system for a pump that provides a fluid flow in an engine.

DESCRIPTION OF RELATED ART

Engines require various fluid flows during operation, for purposes such as cooling, lubrication, and providing fuel for combustion. Fluid flows may be propelled by a pump through a network of pipes and valves on an engine. The flow rate and pressure of a fluid flow that is needed for an engine may vary based on the operation of the engine. Providing fluid flows tailored to engine operation with relative accuracy may require complex control hardware on the engine. Engine gearbox-driven pumping systems comprising a fixed gearbox may be used for various fluid flow applications in an engine. A gearbox pumping and control system transfers mechanical power from the engine to the pump via the gearbox to provide the fluid flow in the engine, and may deliver relatively accurate flows and pressures. However, a gearbox-driven pumping system may require additional air cooling or a return to tank path in order to maintain a target fluid temperature, as fuel recirculation around pump may generate extra heat in the pumping system that needs to be dissipated.

BRIEF SUMMARY

According to one aspect, a fluid pumping system for an engine includes a pump; a summing differential connected to the pump; a gearbox connected to the summing differential, wherein the gearbox causes the pump to rotate to provide a fluid flow in the engine via the summing differential; and a motor connected to the summing differential, wherein the motor adjusts a rotational speed of the pump via the summing differential.

According to another aspect, a method for speed control of a pump to provide a fluid flow in an engine includes powering the pump to rotate by a gearbox connected to a summing differential to provide the fluid flow in the engine; and adjusting a rotational speed of the pump by a motor connected to the summing differential.

Other aspects, features, and techniques of the invention will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:

FIG. 1 illustrates a block diagram of an embodiment of a system for speed control of an engine pump via a summing differential;

FIG. 2 illustrates another embodiment of a system for speed control of an engine pump via a summing differential; and

FIG. 3 illustrates a flowchart of a method for speed control of an engine pump via a summing differential.

DETAILED DESCRIPTION

Embodiments of systems and methods for speed control of an engine pump via a summing differential are provided, with exemplary embodiments being discussed below in detail. A gearbox-driven pumping system may be used in conjunction with a summing differential and a motor to provide a fluid flow in an engine. The gearbox may provide the primary power source to the pump from the engine, while the motor may be used to increase or decrease the rotational speed of the pump in order to meet a target flow requirement (e.g., flow rate and pressure) for the fluid flow in the engine. The gearbox may be sized to input power to the pump from the engine to produce a base rotational pump speed that is determined based on the design of the pump and the requirements of the pumping application. The motor input to the differential may add or subtract rotational speed from the pump shaft in order to make adjustments in the pump speed, as the actual pump flow demand in the engine may vary. The motor may be controlled based on a flow sensor in the engine in order to meet a target flow requirement for the fluid flow. The flow sensor may be part of an electronic engine controller of the engine in some embodiments. In one embodiment, by matching the pumping to the flow requirement, less heat is created in the pumping system, eliminating the need to return fuel to the aircraft tank. This may eliminate the need for relatively complex plumbing and valve systems. The motor may also act as a back-up power source for the pump in the event of a failure in the power transmission path comprising the gearbox.

Embodiments of speed control of an engine pump via a summing differential may be used in conjunction with any appropriate type of engine, including but not limited to an aircraft engine, such as an airplane or helicopter engine, a ground vehicle, a relatively large industrial engine, or a ground-based electric generator. The pump that is powered via the summing differential may provide any appropriate fluid flow in the engine, including but not limited to fuel, oil, air, or glycol. The motor may comprise an electric motor, and may be powered by any appropriate power source, including but not limited to a power grid, an auxiliary power unit (APU), or the engine itself via a generator. The target flow requirement may be based on a current operating condition of the engine. For example, in embodiments where the engine comprises an aircraft engine, during ground idle or at the top of a descent the pump flow target may be low, so the motor may subtract speed from the pump by way of the summing differential to provide a desired flow in the engine. When the aircraft engine is at full power (for example, at takeoff), there is high flow demand, and the motor adds speed to the pump for increased flow. During straight and level flight (for example, during cruising), the motor may provide relatively little or no speed adjustment to the pump, and so that the motor requires relatively little power to maintain the flow at the desired level in the engine.

FIG. 1 illustrates a block diagram an embodiment of a system 100 for speed control of an engine pump via a summing differential. Summing differential 103 receives power inputs from motor 101 and gearbox 102, and causes pump 104 to rotate to provide a fluid flow in engine 105. The fluid flow provided by pump 104 is measured by flow meter 106. Gearbox 102 transfers rotational power from the engine 105 to the pump 104 via the summing differential 103. Motor 101, which may comprise an electric motor, is controlled based by a motor control module 107, which receives input from the flow meter 106. Motor 101 is controlled by the motor control module 107 to speed up or slow down the rotation of the pump 104 (via the summing differential 103) as needed to adjust the fluid flow output by the pump 104 to meet a target flow requirement based on input from the flow meter 106. The motor control module 107 may further control the motor 101 based on the current rotational speed of the motor 101, the current rotational speed of the pump 104, and the current operating conditions of the engine 105 in various embodiments. Motor control module 107 may be part of an electronic engine controller of the engine 105 in some embodiments. The motor control module 107 may be located in any appropriate location with respect to the engine 105.

FIG. 2 illustrates another embodiment of a system 200 for speed control of an engine pump via a summing differential. Summing differential 206 comprises a first leg 207 a and a second leg 207 b. Gearbox 203 is connected to the first leg 207 a of the summing differential 206. Gearbox 203 transfers power received from the engine via engine power input 204 to the pump 205 via the summing differential 206, causing pump 205 to rotate and provide a fluid flow in the engine. Motor 201 is connected to the second leg 207 b of the summing differential 206, and is controlled via flow sensor-based motor control input 202, which controls the motor 201 based on the state of the fluid flow in the engine. The motor 201 acts to speed up or slow down the rotation of the pump 205 via summing differential 206, as needed, to meet a target flow requirement for the fluid flow produced by the pump 205 in the engine. The target flow requirement may be based on a current operating condition of the engine.

FIG. 3 illustrates a flowchart of an embodiment of a method 300 for speed control of an engine pump via a summing differential. In block 301, the pump is powered to rotate by the engine via the gearbox and summing differential, thereby providing a fluid flow in the engine. In block 302, the speed of the pump is adjusted up or down, as needed, by a motor via the summing differential to meet a target flow requirement for the fluid flow in the engine. The motor is controlled based on a flow sensor that measures the fluid flow in the engine. The target flow requirement may be based on a current operating condition of the engine.

The technical effects and benefits of exemplary embodiments include reduction of complexity in a fluid pumping system for an engine while providing fluid flows that may relatively accurately meet engine requirements.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. While the description of the present invention has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications, variations, alterations, substitutions, or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Additionally, while various embodiment of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

1. A fluid pumping system for an engine, comprising: a pump; a summing differential connected to the pump; a gearbox connected to the summing differential, wherein the gearbox causes the pump to rotate to provide a fluid flow in the engine via the summing differential; and a motor connected to the summing differential, wherein the motor adjusts a rotational speed of the pump via the summing differential.
 2. The fluid pumping system of claim 1, wherein the gearbox transfers power from the engine to the pump via the summing differential.
 3. The fluid pumping system of claim 1, wherein the gearbox is connected to a first leg of the summing differential, and wherein the motor is connected to a second leg of the summing differential.
 4. The fluid pumping system of claim 1, wherein the motor reduces or increases the rotational speed of the pump based on a flow meter that measures the fluid flow in the engine.
 5. The fluid pumping system of claim 4, wherein the motor is controlled by an electronic engine controller of the engine based on input from the flow meter.
 6. The fluid pumping system of claim 1, wherein the motor comprises an electric motor.
 7. The fluid pumping system of claim 6, wherein the motor is powered by one of a power grid, an auxiliary power unit (APU), and an engine electrical generator.
 8. The fluid pumping system of claim 1, wherein the fluid flow comprises one of a liquid or a gas.
 9. The fluid pumping system of claim 8, wherein the fluid flow comprises one of fuel, oil, air, or glycol
 10. The fluid pumping system of claim 1, wherein the motor adjusts the rotational speed of the pump to meet a target flow requirement of the fluid flow.
 11. The fluid pumping system of claim 10, wherein the target flow requirement is based on a target operating condition of the engine.
 12. A method for speed control of a pump to provide a fluid flow in an engine, the method comprising: powering the pump to rotate by a gearbox connected to a summing differential to provide the fluid flow in the engine; and adjusting a rotational speed of the pump by a motor connected to the summing differential.
 13. The method of claim 12, wherein the motor adjusts the rotational speed of the pump based on a flow sensor of the fluid flow in the engine to meet a target flow requirement of the fluid flow, wherein the target flow requirement is based on a target operating condition of the engine.
 14. The method of claim 13, wherein, in the event the operating condition of the engine is high, the motor is configured to increase the rotational speed of the pump.
 15. The method of claim 13, wherein, in the event the operating condition of the engine is low, the motor is configured to reduce the rotational speed of the pump.
 16. The method of claim 13, wherein, in the event the operating condition of the engine is steady, the motor is configured to perform no change of the rotational speed of the pump.
 17. The method of claim 12, wherein the gearbox is configured to transfer power from the engine to the pump.
 18. The method of claim 12, wherein the gearbox is connected to a first leg of the summing differential, and wherein the motor is connected to a second leg of the summing differential.
 19. The method of claim 12, wherein the motor reduces or increases the rotational speed of the pump based on a flow meter that measures the fluid flow in the engine.
 20. The method of claim 19, wherein the motor is controlled by an electronic engine controller of the engine based on input from the flow meter. 